Innovation and Interest Rates

Larry Summers, in a speech at the National Association for Business Economics, noted that fancy technology might be depressing interest rates:

Ponder for example that the leading technological companies of this age, I think for example of Apple and Google, find themselves swimming in cash and facing the challenge of what to do with a very large cash hoard. Ponder the fact that WhatsApp has a greater market value than Sony with next to no capital investment required to achieve it. Ponder the fact that it used to require tens of millions of dollars to start a significant new venture. [Significant] new ventures today are seeded with hundreds of thousands of dollars in the information technology era. All of this means reduced demand for investment with consequences for the flow of - with consequences for equilibrium levels of interest rates.

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While he’s right that there are secular trends toward cheaper capital, I’m not sure we can attribute much of that to the information technology era. Even granting that the magnitude of technology is substantial, something I’ll get back to in a minute, it’s important to explore the consequences. I would argue that the information era doesn’t reduce the demand for investment, as Summers proposes, as much as the interest rate elasticity of demand – that is to say firms are less sensitive to changes in the cost of capital. The reason isn’t obvious. Interest rates matter a lot for long-term, capacity building investments—like opening a huge new factory. But software is usually rented on a monthly basis from the firm’s own cash—so interest rates matter a lot less. (Reduced demand and reduced need mean the same thing in English, but not economese).

But that’s coming from the same cash pile Summers is talking about—and it’s still investment. In general it’s not that there’s a lot less investment as much as the factors that affect its demand are changing. This is where we get back to magnitudes. Take a look at software’s share of total private investment:

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There are two stories here. One, in sheer magnitude, software (the blue line) is still only 15 percent of private investment and not significantly higher than points in the past two decades when interest rates were a lot higher. On the other hand, residential investment as a share of private investment, hasn’t changed much in structure since the mid-'60s and is still very sensitive to changes in the interest rate.

The point here is that while WhatsApp didn’t need any real investment, a lot of the economy does, and as sexy as Silicon Valley is, main street America is not irrelevant. There’s another point here, and I’d file it under, as Scott Sumner might say, “never reason from a price change.” The Silicon Valley story tells us that the returns on very small investments can be huge and, under competitive markets, this would imply that the marginal return on capital is falling rapidly after a certain level. However, that isn’t consistent with the broad increase in capital’s share of income we’ve noticed over the past decade or so. In a simple (but empirically powerful) Cobb-Douglas production function, the exponent on capital is its share of total income, and the higher the exponent, the larger the marginal product at any given point (other things equal).

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Of course, other things are never equal, and that’s Sumner’s point.

Summers is right, that to the extent software is significant, there are important implications for the equilibrium interest rate. As the elasticity falls (that is, as the demand curve becomes more vertical) changes in the supply of loanable funds will be felt entirely through interest rate adjustment. So an increase in supply has a lot more potential to keep the economy under a low interest rate environment than before.

Ultimately, this is all pretty speculative. Calculating the importance of interest rates, as an empirical phenomenon, is notoriously difficult (studies disagree, for example, on whether higher interest rates even increase savings)—and observing shifts in the shape of the determining curves is harder still. While interest rates are low for a number of reasons, technology per se may not be one.

The practical point here is that since long-term interest rates are what drive the kind of investment Summers says is dwindling, it’s ever more incumbent that the Fed doesn’t let the term premium on long bonds rise too much. That is, keep quantitative easing hard.

Ashok Rao is a student at the University of Pennsylvania. Read his eponymous blog.